Reference is made to applicant's related application Ser. No. 89,011, now U.S. Pat. No. 4,279,156.
This invention relates to particle collectors and fractionators for both collecting and fractionating particles from a stream of gas. While the invention disclosure may be used in any application requiring the separation of particulate matter from a gaseous medium, the invention is specifically designed for separating and fractionating fine particles of pollutants from the atmosphere incident to air sampling tests.
The particle collector and fractionator should be easy to clean and of simple construction, but nonetheless capable of accurately fractionating and effectively collecting a group of gas suspended particles into a large number of discrete categories of aerodynamic diameters. The accuracy of a particle collector and fractionator is particularly important, and when the collector is being used to collect particles of pollutants from the atmosphere, the accuracy of the particle density measurements should not be affected by air currents. Also, a collector should be convenient and simple to operate either by itself, or in combination with particle filters or other forms of conventional particle collecting and sampling equipment. Another desirable feature of any particle collector and fractionator is its ability to be adjustable for collecting and fractionating particles over a wide range of minimum aerodynamic size. Finally, such a collector should be capable of handling a high volume mass flow rate so as to allow large samples to be taken for biological and chemical analysis.